You will need
- - tools for cutting wire;
- - table of specific resistances;
- - additional resistance.
Identify the substance from which made the guide. Find the specific resistance using the table. Lower the resistance of the conductor having the same conductor, only of substances, the specific resistance is lower. How many times will smaller this value is the number of times decreases the resistance of the conductor.
If possible, reduce the length of the conduit, which is used in the circuit. Resistance is directly proportional to conductor length. If you shorten the conductor in the n times, then the resistance decreases by the same factor.
Increase the cross-sectional area of the conductor. Install conduit with a large cross-section or connect several conductors in parallel in the bundle of wires. How many times will increase the cross-sectional area of the conductor, as many times decreases the resistance of the conductor.
You can combine these methods. For example, to reduce the resistance of the conductor 16 times, replaced it with a conductor, specific resistance of less than 2 times reduce 2 times its length and cross-sectional area 4 times.
To reduce resistance on the part of the chain, attach it in parallel to another resistance, the value of which calculate. Note that when parallel connection, the resistance of circuit is always less than the smallest resistance in the parallel branches. Calculate the required resistancethat must be attached in parallel. To do this, measure the resistance of the circuit R1. Determine the resistance, which should it be – R. then, determine the resistance R2, which should be attached to the resistance R1 in parallel. To do this, find the product of the resistances R and R1 and divide by the difference between R1 and R (R2 = R • R1 / (R1 - R)). Note that condition R1 is always larger than R.
Advice 2: How to find total resistance
Resistance is a kind of ability of the circuit to prevent the passage through it of an electric current. They have a variety of materials, such as copper, iron and nichrome. The total resistance is the resistance of the entire electric circuit as a whole. It is measured in ohms. Need to know the resistance of the circuit to estimate short circuit currents and selection of switching devices.
You will need
- The ohmmeter, measuring bridge, calculator.
To start, determine how the connected elements of an electric circuit relative to each other, as this affects the calculation of the total resistance. The conductors may be in serial or parallel connection. The serial connection is a connection when all elements are linked so that the enclosing the portion of the circuit has a single node, and parallel connection is a connection, when all the circuit elements connected with two nodes and do not have relationships with other nodes.
If you have determined that the conductors in an electrical circuit are connected in series, find the total resistance will not be difficult. Simply add up the resistance of all elements. If you are given the resistance of each conductor, but given their voltage and current of any circuit element, then adding all the voltage, you will know the total voltage. The current strength of each element in a series connection are equal, that is, the total current in the entire circuit equal to a current of any conductor of this chain. And then to find the total resistance, divide the total voltage into amperage.
If the elements are connected in parallel, the total resistance can be found as follows: multiply the resistance of all conductors and divide by their sum. If you are given the resistance of each element but their amperage and voltage of any circuit element, then adding all the amperage you will learn common. Voltage of each element in parallel connection are equal, that is, the total voltage across the circuit equals the voltage of any conductor to this chain. And then to find the total resistance, divide the voltage to the total current.
To determine the total resistance in a circuit, use measuring instruments such as ohmmeter and measuring bridge. They will help you to determine electric resistance.
Be sure to define a method of connecting components in an electrical circuit, as it depends on the correct calculation of the total resistance!